Morris Animal Foundation invites funding requests

 Morris Animal Foundation, one of the largest non-profit animal health research organizations in the
world, is now inviting requests for funding for studies focusing on equine behavior and welfare.

“This call for proposals provides researchers the opportunity to take a closer look at behavior issues that impact the health of equid species,” said Dr. Janet Patterson-Kane, Morris Animal Foundation Chief Scientific Officer.

“We recognize the importance of behavior as a component of animal health and overall welfare. This call will advance our knowledge of equine behavior, with a particular emphasis on guiding interventions and improving well-being.”

Proposals should focus on improving the lives of horses by increasing our understanding of the behavioral domain. This includes areas such as cognition, learning, stereotypies, separation anxiety, affiliative behavior toward (bonding with) humans, equine psychopharmacology, and the effects of equine temperament on welfare. Proposals may involve domesticated or wild horses.

The maximum project duration is 12 months, and the budget cannot exceed $10,000 USD.

This Donor-Inspired Study grant is funded by long-time Morris Animal Foundation supporter, Dr. Wendy Koch. Dr. Koch, a veterinarian, has closely followed equine behavior and welfare research over the years and wanted to increase the amount of funding available for studies in these fields.

All proposals submitted to Morris Animal Foundation will be reviewed by a Scientific Advisory Board. Interested researchers can find additional information, including award types and funding levels at:

https://morrisanimalfoundation.org/apply

Easing intramuscular injections

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Applying topical anaesthetic to the skin a couple of minutes before vaccinating horses can reduce signs of discomfort recent research has shown.

Puncturing the skin for Intramuscular injections and collecting blood samples are common procedures in equine medicine. However, many horses show signs of discomfort, and may become “needle shy”.

Catherine Torcivia  and Sue McDonnell at the University of Pennsylvania School of Veterinary Medicine’s New Bolton Center,  conducted a study to see if  applying topical anaesthetic before inserting the needle reduced the signs of discomfort..

They explain: “Our experience indicates that horses can begin to develop an injection aversion after only one uncomfortable experience. From that point forward, the typical progression for many horses involves increasingly aggressive handling techniques to attempt to restrain or punish increasingly animated avoidance behavior. This experience can quickly lead to conditioned fear that may generalize beyond injections, making those horses dangerously challenging to handle for other health care procedures.”

“If we can reduce the discomfort of injections, we may be able to avoid development of aversions to injections and other health care procedures, thereby improving welfare both at the time of vaccinations and lifelong.”

The study involved semi-feral ponies from the University’s herd. They were restrained in a holding pen while various management procedures were carried out – such as measuring height and weight with a girth tape, body condition scoring, palpating and estimating the size of testicles, and administering oral anthelmintic - as well as administering two intramuscular vaccinations.

Torcivia and McDonnell applied topical anaesthetic (5% an 10% lidocaine) or a  placebo to the injection site two minutes before injecting the ponies.  Each pony was given two vaccinations – one on either side of the neck, and the researchers, blinded to which concentration of ointment had been used, recorded the ponies’ responses at the moment of each injection

They found that reaction scores for both the 5% and 10% lidocaine groups were significantly lower ( ie showed less reaction) than for the control group. The difference between the 5% and 10% lidocaine groups was not significant. 

They conclude that applying topical anaesthetic can reduce the reaction of horses to intramuscular injection.

“Both the 5% and 10% lidocaine products commercially available for numbing human skin were effective when applied only two minutes before vaccination, making the procedure practical for routine use.”

They suggest that further work should be helpful in optimizing benefit from these and other topical numbing preparations.

For more details, see:

Efficacy of Lidocaine Topical Solution in Reducing Discomfort Reaction of Horses to Intramuscular Vaccination
Catherine Torcivia , Sue McDonnell 
Animals (Basel) (2022) 28;12(13):1659.
https://doi.org/10.3390/ani12131659

Strip grazing reduces eating but not moving, new study shows

Studies have already shown that strip grazing is an effective way of restricting grass intake in ponies.

Now, new work indicates the added benefit that eating less doesn’t automatically mean moving less.

Restricting grass intake is an essential part of many weight management programmes. Having shown in a previous study that strip grazed ponies gain significantly less weight than ponies with free access to restricted grazing over a 28-day period, SPILLERS and their research collaborators set out to discover whether eating less as a result of strip grazing also means moving less in the field. 

To evaluate the effects on ‘activity levels’ of ponies strip grazing individually, behavioural data from the previous study was analysed. In addition, a second study was evaluated, that had been carried out in collaboration with the Royal Veterinary College, to look at the effects of strip grazing on the behaviour of ponies turned out in groups.

In the second study 10 ponies were randomly assigned to one of two adjacent paddocks. Both paddocks were the same size, had been managed in the same way and subjectively had the same amount of very limited grazing available. Paddock B was divided into seven strips (using electric fencing) with ponies given access to one additional fresh strip of grazing every day; ponies in paddock A had access to the entire paddock for the duration of the study.

In both studies, behaviour and activity levels were assessed on several occasions using a combination of direct observation and activity monitors attached to the poll strap of the ponies’ headcollars. 

The research team found no significant difference in the over-all time strip grazed ponies spent grazing, standing, or moving regardless of whether a back fence was used or if they were turned out individually or as a group.

“The results of both studies showed that the strip grazed ponies moved just as much as the unrestricted ponies,” said Clare Barfoot RNutr, Marketing and Research and Development Director at Mars Horsecare UK, home of the SPILLERS brand. “Similar amounts of time were spent grazing, standing and locomoting (which included walking, trotting and cantering) within the different groups and encouragingly, performance of behaviours related to stress and frustration were low in both studies too.”

“While we were unsurprised to see that the strip grazed ponies preferred to graze the newly accessible grass and spent most time grazing in the four hours after the fence had been moved, we believe this finding could be useful when deciding if and how those prone to laminitis should have access to grass.”

The researchers are now looking into the effects of strip grazing on the water-soluble carbohydrate (WSC) or ‘sugar’ content of the grass as well as pasture recovery.

For more details, see:

The effect of strip grazing on physical activity and behaviour in ponies.
A Cameron, A Longland, T Pfau, S Pinnegar, I Brackston, J Hockenhull,  PA Harris, NJ Menzies-Gow. (2021).
Journal of Equine Veterinary Science, (2022) 110, 103745. 
https://doi.org/10.1016/j.jevs.2021.103745

Effect of retraining racehorses on gait

(c) Donald Blais  Dreamstime.com

 Retraining of Thoroughbred racehorses for use as saddle horses results in changes in gait more
suited to their new career, according to a study in Korea.

 The research, by Taewoon Jung and Hyoungjin Park, examined the effects of 12-week saddle horse conversion training on Thoroughbred gait.

 Twelve horses, six geldings and six mares, were involved in the study. Their gaits, at walk and canter, were motion-captured before and after saddle horse conversion training. 

 Describing their findings in Applied Sciences, the authors report:

 “The retraining program applied to the Thoroughbreds in this study induced significant changes in the kinematic parameters. After training, retired Thoroughbred racehorses had shorter stride lengths and a reduced center of mass displacement, center of head displacement, displacement between the center of the head and the center of the neck, and head–neck angles, bearing in mind that no significant differences in the duration of gaits and the center of mass and head velocities were observed.”

 “Although the effect of retraining was not statistically significant in the stride lengths, all stride lengths were reduced in both walk and canter.” Changes were more marked in the right fore and hind limbs than in the left limbs.

 All races on Korean tracks run in a counterclockwise direction. The authors suggest that the resulting asymmetry explains the greater changes in the stride lengths of the right compared with the left. “These changes mean that the retraining positively affected the imbalance of the horse’s body”

 They conclude: “Through saddle horse conversion training, the horse’s movement changes may be considered as the habitual movements in the life of a racehorse being gradually transformed into ideal movements for a saddle horse.”

           

For more details, see:

The Effect of 12 Weeks of Saddle Horse Conversion Training on Thoroughbred Horse Gait
Taewoon Jung and Hyoungjin Park
 Appl. Sci. 2022, 12(13), 6411;
https://doi.org/10.3390/app12136411

International Equitation Science Conference

 

The International Society for Equitation Science conference returns this year after missing 2020 and taking place
online last year,

Hartpury University and College, Gloucester, is set to host the 18^th annual event from 10 - 12 August, with the title ‘Succeed with Science: Performance, Practice and Positive Partnerships’.

Delegates have the option to attend either in-person or online.

Over three days, the event aims to give delegates a fresh perspective on the current state of Equitation Science with thought-provoking plenaries, workshops, research presentations, keynotes, and research studies. Here’s a rundown of the key conference themes.

Performance: Dr Andrew Hemmings and Linda Greening will take a trip inside the horse’s mind with a head-first approach to equine management and training, while Dr David Marlin and Prof Tim Parkin will explore relationships between equine performance and welfare, by examining how we can define and measure performance, and the role science can play to enhance health and welfare – not just competitive success.

Practice: Dr Marc Pierard will showcase how learning theory can be applied in the ridden horse, while Christopher Bartle FBHS will discuss his personal philosophy for training horse and rider partnerships. Prof Lars Roepstroff and Dr Russell Mackechnie-Guire will consider how rider performance and horse and rider asymmetries can influence training and performance and affect quality of life for the ridden horse.

Positive Partnerships: The horse-human relationship is the foundation of positive partnerships, and the conference will consider this partnership from both the horse and the human perspective. Dr Natalie Waran will explore how this knowledge can underpin and promote ethical equitation practices and positive relationships alongside Dr Hayley Randle and Dr Jane Williams..

Professor Natalie Waran, Chair of Trustees at ISES and Executive Dean and Professor (One Welfare) at the Eastern University of Technology (EIT) New Zealand, said:

“It’s important that we remember that a partnership is a two-way exchange, with both parties enjoying the benefits resulting from the interaction. If we are to be certain that horses can enjoy a positive experience when being handled, trained, ridden, driven and in performance, we need to ensure that we know what is positive from the horse’s perspective, and how we provide for this in practice.

“This year’s ISES conference theme ‘Succeed with Science’ will provide an opportunity for scientists, students, and practitioners to engage with a rich mix of the latest equitation science research and advanced practice, as well as showcase how technology can be harnessed to further our knowledge about how to ensure that the horse-human partnership is mutually rewarding.”

For more details, see:

https://equitationscience.com/conferences/

 

Drones for monitoring feral horses

© Mantvydas Krikstaponis Dreamstime.com

 Drones provide a way to monitor feral horse populations while causing only low levels of disturbance.

Javier Lenzi and co-workers at the Department of Biology, University of North Dakota, evaluated the behavioural response of feral horses in the Theodore Roosevelt National Park in North Dakota, to a fixed wing drone (Trimble UX5), as part of larger surveying project. 

 

The drone has a 1 metre wingspan, a rear propellor and weighs 2.5 kg. It was flown directly above the animals at an altitude of 120m. Video recordings were analysed by the research team in ten second sections.

            

They found that, although horses did respond to the presence of the drone, they did not show escape responses, which would have been expected in ground surveys or traditional low-level aerial surveys. Feeding, traveling, and vigilance behaviours increased, while resting and grooming decreased in response to the drone flight.

 

The researchers also observed the reaction of bison to the drone. Bison also showed increased feeding and travelling and decreased resting and grooming.

 

Reporting their findings in the journal Drones, the authors suggest that “the drone used in this study might have been perceived by horses and bison as low risk, possibly given the high altitude and small drone size. Our results showed that individuals did not display escape behaviour, and even increased feeding activities in response to drone flights at 120 m above ground level.”

 

They conclude that that drones “may serve as an appropriate tool for surveys of these species with low levels of disturbance, unlike other stressful sources.”

 

For more details, see:

 

Feral Horses and Bison at Theodore Roosevelt National Park (North Dakota, United States) Exhibit Shifts in Behaviors during Drone Flights 

Javier Lenzi, Christopher J. Felege, Robert Newman, Blake McCann and Susan N. Ellis-Felege

Drones (2022), 6(6), 136.

https://doi.org/10.3390/drones6060136

Obesity and cardiovascular changes

 Obesity has a significant impact on the structural changes in cardiovascular tissue in horses, a recent study has found.

Obesity is known to have significant adverse effects on horse health.  Laminitis is an obvious example, but it can also contribute to other problems such as those affecting soundness or fertility

 

In humans, obesity is recognised as a risk factor for cardiovascular problems. However, until now there has been little research into the effect of obesity on the wider cardiovascular tissues of horses. 

 

A recent study by Natalia Siwinska and colleagues at the Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences assessed the impact of obesity on the microscopic structure of the heart muscle and selected arteries in horses.

 

They conducted post-mortem examinations on 19 draft slaughter horses, comparing specimens from twelve extremely obese (body condition score (BCS 9/9) and seven with normal body condition (BCS 4-5/9). They examined specimens of heart muscle and major blood vessels (aorta, pulmonary, coronary and palmar arteries). A report of the work is published in the journal Animals.

 

The researchers found significant changes in the heart muscle and vessels in obese horses compared with those in normal condition. 

 

Obese animals had increased amounts of pericardial and cardiac fat, and the intima (the inner layer) of the pulmonary artery, coronary arteries and palmar arteries was thicker, compared with the healthy animals. They also found changes in palmar arteries in obese horses, which had a larger lumen diameter and the lumen-to-total diameter ratio compared to the control group.

 

The structural changes that they found are like those observed in people. The researchers suggest that these changes “may be an indicator of subclinical dysfunction, which could lead to severe disease.” 

 

They suggest that the direct effects of obesity on cardiovascular health and function in horses require further exploration

 

 

For more details, see:

 

Influence of Obesity on Histological Tissue Structure of the Cardiovascular System in Horses. 

Siwinska, N.; Janus, I.; Zak-Bochenek, A.; Noszczyk-Nowak, A. 

Animals 2022, 12, 732.

https://doi.org/10.3390/ani12060732

Worm control in Hungary

For some time now, experts have advocated a targeted or strategic approach to worm control, rather than relying on treatment at regular intervals, because of the growing threat of anthelmintic resistance. 

 

A traditional approach to equine parasite control, involving rotating anthelmintic treatments at regular intervals, is still widely used in Hungary, according to a recent report. Almost no farms utilize faecal egg counts (FECs) on a regular basis to guide deworming treatments. 

 

Kinga Joó and her co-workers conducted a study to investigate risk factors associated with strongylid egg counts.The work is reported in Veterinary Parasitology: Regional Studies and Reports.

 

The research team collected faecal samples from 216 sport and pleasure horses, kept on 13 farms in Hungary. The horses ranged from 5 months to 30 years of age, and had last received anthelmintic (dewormer) treatment at least 60 days previously.

 

None of the farms involved in the study had previously used FECs to guide deworming treatments on a regular basis. 

 

Analysis of the results showed:

• most of the faecal worm egg production was due to a limited number of horses. Only 22% of horses were responsible for 80% of the total strongyle egg output. This is in line with findings of other studies.

• young horses (less than 5 years of age) had significantly higher FECs than horses 5–17 years old and those aged over 17 years.

• horses treated with benzimidazoles (eg fenbendazole) at least once a year had significantly higher FECs than equids that had not received benzimidazoles.

• horses kept at very high stocking densities (>30 horses/ha) had significantly higher EPG-values than horses kept at lower stocking densities.

 

They conclude “the results demonstrate the value of FEC monitoring and indicate that the efficacy of benzimidazoles should be investigated in Hungary. Moreover, our findings demonstrate that reducing stocking density should be considered in cases of high strongylid FECs.”

 

 

For more details, see:

 

Evaluation of risk factors affecting strongylid egg shedding on Hungarian horse farms

Kinga Joó, Roxána L Trúzsi, Csenge Zs Kálmán, Virág Ács, Szilárd Jakab, András Bába, Martin K Nielsen.

Vet Parasitol Reg Stud Reports (2022) 27:100663

doi: 10.1016/j.vprsr.2021.100663

Can probiotics help reduce parasite shedding in foals?

Probiotics are frequently added to horses’ diets with the goal of promoting a healthy microbial environment in the intestinal tract. But does their use have any effect on the worm burden in the gut?

 Research by Dr Robert Jacobs and colleagues at the Purina Animal Nutrition Center suggests that giving probiotics to foals may reduce the number of intestinal parasites they carry.

 

The research was presented at the 2021 virtual Equine Science Symposium. An abstract is published in the Journal of Equine Veterinary Science.

 

Twenty-nine quarter horse foals took part in the study over three consecutive foaling seasons.  Fifteen foals chosen at random were given a probiotic paste twice daily for eight days starting two days after being born. Fourteen foals received no probiotic.

 

(Each dose of probiotic paste contained 2.5 × 109 cfu each of B. subtilis, B. infantis, and L. acidophilus.)

 

The groups were managed similarly – being fed twice daily and being turned out into dry lots during the day.

 

When the foals were 150 days old, the researchers collected faecal samples. The foals had not received any anthelmintic before then. 

 

Analysis showed that “foals in the treatment group had fewer strongyle (1.07 vs 4.57/gm of feces; P = 0.02) and roundworm eggs (101.33 vs 216.00/gm of feces; P = 0.01) than those from the control group.”

 

The authors conclude “that the administration of the probiotic paste to otherwise identically managed groups of foals may reduce their overall parasite load. “

 

They suggest that “further research is needed to understand the mechanisms by which this is occurring and to determine if these effects persist.”

 

For more details, see:

 

Probiotic administration post-foaling may reduce parasite shedding in foals

R.D.Jacobs, M.L.Jerina, B.A.Tremayne

Journal of Equine Veterinary Science (2021)

Volume 100, May 2021, 103565

https://doi.org/10.1016/j.jevs.2021.103565

Smoothing the transition for retired Australian racehorses

What physical and behavioural qualities are desired in retired racehorses to help them adapt to a new equestrian career? 

Mollie Buckley, at the Charles Sturt School of Agricultural, Environmental and Veterinary Sciences, in Australia, is conducting research to address the current lack of knowledge about what makes former racehorses succeed in their new occupations. 

 

She is looking for owners of retired racehorses in Australia to take part in an online survey. The project aims to identify attributes shown in retired racehorses (Thoroughbred and Standardbred) that are enjoying a successful post-racing career.

 

The survey will ask questions related to the characteristics and temperament of the retired racehorse, both on the ground and when ridden.

 

Buckley hopes that this research will help the Australian racing industry smooth the process of re-homing racehorses after they retire from the track.

All previous and current owners of retired racehorses are encouraged to participate in the research.

 

The online survey closes on Monday 25 July, and takes approximately 20 minutes to complete.

 

For more details, and to complete the survey, go to:

 

https://www.research.net/r/Retired-Racehorses

Eriskay Ponies sought for genetic study

© Thomas Langlands | Dreamstime.com

 Eriskay pony owners are asked to take part in a genetic study to help protect this critically endangered
native breed.

The Eriskay Pony Society is working with genetics experts at Nottingham Trent University (NTU) and the Rare Breeds Survival Trust (RBST) to carry out the biggest ever survey of Eriskay Pony DNA.

 

The Eriskay is a small pony, standing 124-138cm (12.0-13.2 hands) high. Traditionally they worked on the crofts (smallholdings), carrying loads such as seaweed, and peat, in baskets (“creels”) slung over their backs. They were also used for light draught work. 

 

Eriskay ponies are among the last representatives of the original native ponies of the Western Isles of Scotland, and are probably one of the oldest and purest breeds in the United Kingdom. 

 

Their isolation on the remote island of Eriskay in the Outer Hebrides helped protect them from introduction of other breeds. On many of the Scottish islands, native ponies were “improved” by breeding with larger stallions. This did not happen on Eriskay, leaving a stock of pure-bred ponies.

 

By the early 1970’s the Eriskay Pony population had dwindled to about 20 animals. Controlled breeding programmes have restored the population to over 400 animals around the world. However, the Eriskay Pony is still classed as “critical” by the Rare Breeds Survival Trust,

 

The DNA analysis, being carried out by NTU’s Medical Technologies Innovation Facility and School of Animal, Rural and Environmental Sciences, involves Professor Philippe Wilson, Dr Samuel White and Dr Andy Dell. The work is supported by funding from the Horserace Betting Levy Board.

 

Professor Wilson explained: “We will be employing state of the art genotyping technologies in order to support a detailed understanding of the genetic status of the Eriskay and will work closely with the breed society to really deliver impact directly to the breeders.”

 

The results of the analysis will be used, in conjunction with the Rare Breed Survival Trust’s Equine Conservation project, to help inform future breeding plans and decision making for this critically endangered breed.

 

Catriona Rowan, Chair of the Eriskay Pony Society explained: “This is a very welcome step forward in our efforts to protect and promote this ancient yet versatile breed.

 

“With such a small gene pool we cannot just rely on the look of ponies and studbook information to make our breeding matches. 

 

She explained “This study, which is open to ANY Eriskay Pony registered with a recognised Eriskay breed Society, either The Eriskay Pony Society or Comann Each Nan Eilean (CENE), will give us a great foundation with which to work. It will be a baseline of information for use in our work with the RBST’s Equine Conservation Project which requires us to provide complex information about our genetic profiles. 

 

“Our work with Nottingham Trent University will give us assessment of genetic variation and molecular basis of inbreeding within the Eriskay Pony breed which will then be collated in an Eriskay Pony Genetic Archive. 

 

“It’s easy for Eriskay owners to get involved. Simply apply to us by emailing info@eriskaypony.org for a testing kit and we will send it free of charge. It’s a simple process using a hair sample, which must be returned to us by the end of July. 

 

“The more samples we have the better the overall picture we can build of the breed and the more useful the information will be. And ANY registered Eriskay Pony can make a contribution, no matter the age or breeding status, so it’s a great way for all owners to support the future of the breed.

 

For more details, or to order a free DNA kit, contact info@eriskaypony.org. Samples must be returned by the end of July.

Signs of moxidectin resistance

 Experts have been warning for some time of the danger of ending up with no effective
anthelmintics (dewormers). 

All the available classes of anthelmintic have shown declining efficacy as worms, particularly the cyathostomins (small redworms), become resistant. Moxidectin, a more recent addition to the arsenal is particularly useful for its action against encysted larvae. Until now it has remained relatively unscathed in the battle to hold back the advance of anthelmintic resistance. 

 

However, it seems now that the doomsday scenario is getting nearer as researchers in Australia have shown signs of resistance to moxidectin and combinations of anthelmintics.

 

Ghazanfar Abbas and co-workers conducted a study to assess the efficacy of commonly used anthelmintics against cyathostomins in Australian thoroughbred horses.

They carried out drug efficacy trials on two Thoroughbred stud farms in Victoria, Australia.

Horses were treated with single and combinations of anthelmintics. The researchers used the faecal egg count reduction test (FECRT) to assess the efficacy and egg reappearance period (ERP) of the anthelmintics. 

 

After treatment with an effective anthelmintic the faecal worm egg count (FEC) would be expected to be substantially reduced a couple of weeks later. So, for moxidectin, anything less than a 95% reduction in FEC two weeks after treatment would be taken as an indication of resistance.

 

The worm egg reappearance period (ERP) is the time taken for eggs to reappear in the faeces after successful treatment. It gives an early indication of the development of resistance. 

 

The research team found resistance to various anthelmintics and anthelmintic combinations, (including oxfendazole, abermectin and an oxfendazole/pyrantel combination).  

 

Although moxidectin was highly effective in one farm, producing a 100%  reduction in egg count two weeks after treatment, it showed a shortened ERP. (5 weeks – compared with the expected ERP when the drug is effective of 10 – 12 weeks). Resistance to moxidectin was found on the second farm with reduced efficacy of 90%.

A full report is published in Parasites and Vectors.

 

The authors conclude that the study provides the first evidence of moxidectin and multidrug-resistant (abermectin and combinations of anthelmintics) in cyathostomins in Australia. They suggest the need for continuous surveillance of the efficacy of currently effective anthelmintics and large-scale investigations to assess the ERP for various anthelmintics.

 

For more details, see:

 

Cyathostomin resistance to moxidectin and combinations of anthelmintics in Australian horses

Ghazanfar Abbas, Abdul Ghafar, John Hurley, Jenni Bauquier, Anne Beasley, Edwina J. A. Wilkes, Caroline Jacobson, Charles El-Hage, Lucy Cudmore, Peter Carrigan, Brett Tennent-Brown, Charles G. Gauci, Martin K. Nielsen, Kristopher J. Hughes, Ian Beveridge & Abdul Jabbar 

Parasites & Vectors volume 14, Article number: 597 (2021)

https://doi.org/10.1186/s13071-021-05103-8

 

See also the American Association of Equine Practitioners Parasite Control Guidelines: 

 

https://aaep.org/sites/default/files/Guidelines/AAEPParasiteControlGuidelines_0.pdf

Treating sarcoids with IL-2

A feline interleukin-2 immunomodulator (ALVAC-fIL2) shows promise as a possible treatment for equine sarcoid, a pilot study has shown.

Sarcoids are the most common skin tumour in horses. Currently there is no universally effective treatment, and if treatment fails the sarcoids will often come back worse than they were in the first place. Although the disease is rarely life-threatening, many horses with sarcoids are euthanased because the condition is untreatable or because the horse is unsellable. 

 

Interleukin (IL)-2 is one of the key cytokines (proteins involved in cell signalling). It stimulates cell mediated immunity, activating a range of T-cells. IL-2 is used in human medicine, including for treating cancerous conditions such as metastatic renal cell carcinomas and metastatic melanoma.

 

A canarypox virus vector, which has been genetically modified to contain a gene to produce IL-2, was used in the study. (The product is licenced for use in the treatment of fibrosarcoma in cats.) The technology is widely used in the production of vaccines for horses and other species, including some equine influenza and West Nile virus vaccines.

 

Corey Saba, of the University of Georgia College of Veterinary Medicine, Athens Georgia, and colleagues conducted a pilot study, which has been reported in the Journal of Veterinary Internal Medicine. The work was funded by Boehringer Ingelheim. 

 

Fourteen otherwise healthy horses were included in the study. For a start, each sarcoid was measured and photographed, then injected with 1ml ALVAC-fIL2 divided between four or five different sites. Treatment was repeated 1,3 and 7 weeks later.

 

The research team monitored the response for at least a year after the final treatment. They found that size of the sarcoid reduced in 12 of the 14 horses in the study, with complete remission occurring in seven cases (50%). Partial remission occurred in a further five (35%) 

 

An initial response was noted 34 – 406 days (median 89 days) after starting the treatment, and the best response occurred after 56 – 406 days (median 211 days). 

 

Other than transient mild-moderate focal inflammation in two horses, the injections were well-tolerated.

 

The researchers conclude “our results provide evidence that ALVAC-fIL2 is a safe, cosmetic, and effective treatment for sarcoid tumors in horses. Furthermore, our results provide a basis for a larger, placebo-controlled study to better define the role of this treatment in sarcoid tumors in horses.”

 

For more details, see:

 

ALVAC-fIL2, a feline interleukin-2 immunomodulator, as a treatment for sarcoids in horses: A pilot study

Corey Saba, Randall Eggleston, Andrew Parks, John Peroni, Eric Sjoberg, Shelbe Rice, Jesse Tyma, Jarred Williams, Deborah Grosenbaugh, A. Timothy Leard

Journal of Veterinary Internal Medicine (2022);1–6.

https://doi.org/10.1111/jvim.16425 

Wild parsnip and photo-dermatitis

Wild parsnip has been implicated as a cause of photodermatitis in horses.

 

Clinicians at the Freie Universität Berlin in Germany investigated a series of cases in which horses showed signs of inflammation of unpigmented skin.

 

Judith Winter and colleagues examined nine horses from stables in Berlin and Brandenburg, Germany, which showed variable degrees of erythema, scaling, crusting and necrosis of unpigmented skin on the head and prepuce. Most horses also showed signs of eye involvement: including conjunctivitis, photophobia and blepharitis (inflammation of the eyelids).

 

The clinicians found that, although the horses came from three separate yards, all stables were provided with hay from the same supplier.

 

Analysis of the hay showed that it contained large amounts of wild parsnip plants, including seeds and roots.

 

Wild parsnip (Pastinaca sativa) is widespread in Europe. It contains photodynamic pigments, known as furocoumarins. Contact with parts of the plant that contain the toxins, followed by exposure to sunlight, may cause photodermatitis, keratoconjunctivitis and uveitis. It is thought that lesions can occur due to both systemic uptake and direct topical contact.

 

Horses were treated with systemic anti-inflammatory medication as necessary, combined with topical treatment. They were protected from sunlight by being kept in a dark environment or by being treated with sunscreen and facemasks. Depending on the severity of the signs, treatment lasted from 6–30 days

 

Full details of the cases are published in BMC Veterinary Research. 

 

 

For more details, see: 

 

Photodermatitis and ocular changes in nine horses after ingestion of wild parsnip (pastinaca sativa)

JC Winter, K Thieme, JC Eule, E-M Saliu, O Kershaw, H Gehlen (2022).

BMC Vet Res 18, 80 

https://doi.org/10.1186/s12917-022-03162-2

Investigating worm control measures

 Horses and foals can carry many different parasitic worms in their intestines, some of which can cause severe disease. 

 

 Over recent years it has become recognised that some of the more important worms are developing resistance to the anthelmintics (dewormers) that are used to control them.

 

The seriousness of the problem is highlighted by the fact that resistance to all currently available classes of anthelmintics has been reported in both the cyathostomins (small redworm) and ascarids (large roundworm). Furthermore, there is currently no prospect of any new drugs in the pipeline.

 

It is becoming accepted that we need to adopt a more sustainable approach to deworming.

 

In a letter to the Veterinary Record, Dr Tim Mair and colleagues announced the launch of a collaborative project (ProjectWORMS) which they hope will produce recommendations about the best and safest way to prevent serious worm infestations, whilst limiting the further development of resistance to wormers.

 

The first step is to investigate current thinking and management practices with two online questionnaires – one for horse owner/keepers and one for stud owner/managers. This information is important to be able to develop and promote new and alternative ways of controlling worms that do not add to the problem of anthelmintic resistance

 

Dave Rendle, President Elect of the British Equine Veterinary Association (BEVA) said: “BEVA are pleased to be able to support this important piece of work which will inform decision-making around anthelmintic stewardship going forward. Anthelmintic resistance presents a serious and imminent threat to the equine industry."

 

To take part in the online survey, and for more information, see:

For horse owners/keepers: https://www.surveymonkey.co.uk/r/WORMSowner

And 

For stud owners/managers: https://www.surveymonkey.co.uk/r/WORMSstud

US vets help sought for back pain study

 Equine veterinarians in the United States are asked to complete a short online survey on the diagnosis, treatment and management of primary back pain.

 Marianne E. Marshall-Gibson is conducting the research as part of her American College of Veterinary Sports Medicine & Rehabilitation residency studies.

 

The goal is to determine 1) the preference of practitioners when treating primary back pain and 2) the preference of practitioners for treating impinging spinous processes ("kissing spine") in horses in the United States.

 

The survey is open until May 31^st, and can be accessed by the following link:

 

https://docs.google.com/forms/d/e/1FAIpQLSeaseBD40iLcO2VEO3B8zsMkO-4heQ-IfcqDEmM6sS_Lb-6hQ/viewform

Do ponies avoid salt in drinking water?

 Ponies accept drinking water containing low levels of salt and this could potentially be used to help rehydration, according to a recent study.

 Horses lose heat by sweating and in doing so lose sodium as well as water. Sodium plays an important role in numerous functions throughout the body. An increase in plasma sodium concentration is a trigger for thirst.

 

Horse sweat contains high levels of sodium (Na). Excessive sweating may result in the loss of so much sodium that the plasma sodium concentration does not increase enough to trigger drinking. So heavily sweating horses may not voluntarily drink enough water to replenish their body fluids.

 

Could dilute saline solutions be used as drinking water to help combat sodium loss and dehydration? 

 

A study in Germany by Nick Enke and colleagues assessed whether Shetland ponies would notice and tolerate different salt (NaCl) concentrations in their drinking water.

 

Six non-pregnant and non-lactating mares were enrolled in the study, which consisted of three phases. In the first phase only fresh water was provided, as a control. In the second phase, a pairwise-preference test, ponies were given a choice between fresh water and one of six different saline solutions. Finally, the ponies were offered a choice of fresh water and five different NaCl concentrations at the same time.

 

A full report of the work is published in the Animal Science Journal.

 

The researchers report that during the pairwise test, the ponies did not distinguish between fresh water and 0.25% NaCl-water, but demonstrated a clear preference for water containing 0.5%NaCl. Ponies consistently avoided NaCl concentrations above 0.75%. During the free-choice test, the ponies showed a pronounced preference of fresh over saline water. 

 

They noted that sodium intake from a salt lick was not reduced in response to higher sodium intakes in the water. 

 

They conclude: “The ponies exhibited a remarkable sensory discrimination capacity to detect different NaCl concentrations in their drinking water. The acceptance of solutions with low NaCl levels (0.25/0.5%) without adverse effects demonstrates potential as rehydration solution for voluntary intake.”

 

 

For more details, see:

 

Sensitivity of ponies to sodium in the drinking water

Nick Enke, Lea Brinkmann, Karl-Heinz Südekum, Ernst Tholen, Martina Gerken

Anim Sci J (2022);  93(1):e13697.

https://doi.org/10.1111/asj.13697